Electro Chemistry Book Back Practice Test

12th Standard Chemistry — Electro Chemistry: Book Back Online Practice Test

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The number of electrons that have a total charge of 9650 coulombs is

A.\(6.22 \times 10^{23}\) B.\(6.022 \times 10^{24}\) C.\(6.022 \times 10^{22}\) D.\(6.022 \times 10^{-34}\)

Consider the following half cell reactions: \(Mn^{2+} + 2e^- \rightarrow Mn\) \(E^\circ = -1.18V\) \(Mn^{3+} + e^- \rightarrow Mn^{2+}\) \(E^\circ = 1.51V\) The \(E^\circ\) for the reaction \(3Mn^{2+} \rightarrow Mn + 2Mn^{3+}\) and the possibility of the forward reaction are respectively.

A.2.69V and spontaneous B.-2.69V and non spontaneous C.0.33V and Spontaneous D.4.18V and non spontaneous

The button cell used in watches function as follows \(Zn (s) + Ag_2O (s) + H_2O (l) \rightleftharpoons 2 Ag (s) + Zn^{2+} (aq) + 2OH^- (aq)\) the half cell potentials are \(Ag_2O (s) + H_2O (l) + 2e^- \rightarrow 2Ag (s) + 2 OH^- (aq)\) \(E^\circ = 0.34V\) and \(Zn^{2+} (aq) + 2e^- \rightarrow Zn (s)\) \(E^\circ = -0.76V\). The cell potential will be

A.0.84V B.1.34V C.1.10V D.0.42V

The molar conductivity of a \(0.5 \text{ mol dm}^{-3}\) solution of \(AgNO_3\) with electrolytic conductivity of \(5.76 \times 10^{-3} \text{ S cm}^{-1}\) at 298 K is

A.\(2.88 \text{ S cm}^2 \text{ mol}^{-1}\) B.\(11.52 \text{ S cm}^2 \text{ mol}^{-1}\) C.\(0.086 \text{ S cm}^2 \text{ mol}^{-1}\) D.\(28.8 \text{ S cm}^2 \text{ mol}^{-1}\)

Using the appropriate molar conductances at infinite dilution in water at 25 \(^\circ\)C: \(\Lambda_{KCl}^\circ = 149.9\), \(\Lambda_{KNO_3}^\circ = 145.0\), \(\Lambda_{HCl}^\circ = 426.2\), \(\Lambda_{NaOAc}^\circ = 91.0\), and \(\Lambda_{NaCl}^\circ = 126.5 \text{ S cm}^2 \text{ mol}^{-1}\). Calculate \(\Lambda_{HOAc}^\circ\).

A.517.2 B.552.7 C.390.7 D.217.5

Faraday constant is defined as

A.charge carried by 1 electron B.charge carried by one mole of electrons C.charge required to deposit one mole of substance D.charge carried by \(6.22 \times 10^{10}\) electrons

How many faradays of electricity are required for the following reaction to occur: \(MnO_4^- \rightarrow Mn^{2+}\)

A.5F B.3F C.1F D.7F

A current strength of 3.86 A was passed through molten Calcium oxide for 41 minutes and 40 seconds. The mass of Calcium in grams deposited at the cathode is (atomic mass of Ca is \(40 \text{ g/mol}\) and 1F = 96500 C).

A.4 B.2 C.8 D.6

During electrolysis of molten sodium chloride, the time required to produce 0.1 mole of chlorine gas using a current of 3A is

A.55 minutes B.107.2 minutes C.220 minutes D.330 minutes

Q10

The number of electrons delivered at the cathode during electrolysis by a current of 1A in 60 seconds is (charge of electron = \(1.6 \times 10^{-19} \text{ C}\))

A.\(236.22 \times 10^{...}\) B.\(6.022 \times 10^{20}\) C.\(3.75 \times 10^{20}\) D.\(7.48 \times 10^{23}\)

Q11

Which of the following electrolytic solution has the least specific conductance

A.2N B.0.002N C.0.02N D.0.2N

Q12

While charging lead storage battery

A.\(PbSO_4\) on cathode is reduced to Pb B.\(PbSO_4\) on anode is oxidised to \(PbO_2\) C.\(PbSO_4\) on anode is reduced to Pb D.\(PbSO_4\) on cathode is oxidised to Pb

Q13

Among the following cells I) Leclanche cell II) Nickel – Cadmium cell III) Lead storage battery IV) Mercury cell Primary cells are

A.I and IV B.I and III C.III and IV D.II and III

Q14

Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because

A.Zinc is lighter than iron B.Zinc has lower melting point than iron C.Zinc has lower negative electrode potential than iron D.Zinc has higher negative electrode potential than iron

Q15

Assertion : pure iron when heated in dry air is converted with a layer of rust. Reason : Rust has the composition \(Fe_3O_4\)

A.if both assertion and reason are true and reason is the correct explanation of assertion. B.if both assertion and reason are true but reason is not the correct explanation of assertion. C.assertion is true but reason is false D.both assertion and reason are false.

Q16

In \(H_2-O_2\) fuel cell the reaction occurs at cathode is

A.\(O_2(g) + 2H_2O(l) + 4e^- \rightarrow 4OH^-(aq)\) B.\(H^+(aq) + OH^-(aq) \rightarrow H_2O(l)\) C.\(2H_2(g) + O_2(g) \rightarrow 2H_2O(g)\) D.\(H^+ + e^-- \rightarrow \frac{1}{2}H_2\)

Q17

The equivalent conductance of M/36 solution of a weak monobasic acid is 6 mho \(cm^2\) equivalent –1 and at infinite dilution is 400 mho \(cm^2\) equivalent –1. The dissociation constant of this acid is

A.\(1.25 \times 10^{-6}\) B.\(6.25 \times 10^{-6}\) C.\(1.25 \times 10^{-4}\) D.\(56.25 \times 10^{-6}\)

Q18

A conductivity cell has been calibrated with a 0.01M, 1:1 electrolytic solution (specific conductance (\(\kappa = 1.25 \times 10^{-3} S cm^{-1}\)) in the cell and the measured resistance was 800 \(\Omega\) at \(25^\circ C\). The cell constant is,

A.\(10^{-1} cm^{-1}\) B.\(10^1 cm^{-1}\) C.\(1 cm^{-1}\) D.\(125.7 \times 10^{-1}\)

Q19

Conductivity of a saturated solution of a sparingly soluble salt AB (1:1 electrolyte) at 298K is \(1.85 \times 10^{-5} S m^{-1}\). Solubility product of the salt AB at 298K \(\Lambda^\circ_m(AB) = 14 \times 10^{-3} S m^2 mol^{-1}\)

A.\(125.7 \times 10^{-6}\) B.\(1.32 \times 10^{-12}\) C.\(7.5 \times 10^{-12}\) D.\(1.74 \times 10^{-12}\)

Q20

In the electrochemical cell: \(Zn | ZnSO_4 (0.01M) || CuSO_4 (1.0M) | Cu\), the emf of this Daniel cell is \(E_1\). When the concentration of \(ZnSO_4\) is changed to 1.0M and that \(CuSO_4\) changed to 0.01M, the emf changes to \(E_2\). From the above, which one is the relationship between \(E_1\) and \(E_2\)?

A.\(E_1 < E_2\) B.\(E_1 > E_2\) C.\(E_1 \geq E_2\) D.\(E_1 = E_2\)

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About this Electro Chemistry test

This free online practice test covers Electro Chemistry from the 12th Standard Chemistry (Samacheer Kalvi) syllabus. Choose the number of questions and an optional time limit, then answer and submit — everything is checked in your browser, with the correct answers and a worked explanation shown at the end. For the full solutions to every question in this set, see the solved MCQs page.

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